Catalytic Dicyanative 5-exo- and 6-endo-Cyclization Triggered by Cyanopalladation of Alkynes
作者:Shigeru Arai、Yuka Koike、Atsushi Nishida
DOI:10.1002/adsc.200900813
日期:2010.3.22
A stereoselective dicyanative 5‐exo‐ and 6‐endo‐cyclization using various enynes has been investigated. The mode of cyclization is critically controlled by the structure of the substrates. For example, N‐allyl derivatives prefer 5‐exo‐cyclization, while methacryloyl amides are transformed to the corresponding lactams with tetra‐substituted carbons at the alpha‐position via 6‐endo‐cyclization. Both
立体选择性dicyanative 5-外-和6-内-cyclization使用各种烯炔进行了研究。环化的模式由底物的结构严格控制。例如,N-烯丙基衍生物更喜欢5- exo-环化,而甲基丙烯酰胺则通过6-内环化转化为α-位带有四取代碳的内酰胺。这两个反应都包括syn在初始步骤中氰氰化成碳碳三键,然后依次环化,然后在一个操作中进行还原消除,即可构建高度官能化的氮杂环。还描述了合适的基材的范围和提出的机理。